Sign Out
The metabolism of budesonide is primarily mediated by CYP3A4. Inhibitors of this enzyme, e.g. itraconazole, ketoconazole, ritonavir, nelfinavir, ciclosporin, ethinylestradiol, cobicistat and troleandomycin can therefore increase systemic exposure to budesonide several times (see Precautions).
This is of little clinical significance for a short term treatment (1-2 weeks), but should be taken into account for long term treatment.
Co-treatment with cobicistat-containing products is expected to increase the risk of systemic side-effects. The combination should be avoided unless the benefit outweighs the increased risk of systemic corticosteroid side-effects, in which case patients should be monitored for systemic corticosteroid side-effects.
Since there is no data to support a dosage recommendation, the combination should be avoided. If this is not possible, the period between treatments should be as long as possible and a reduction of the budesonide dose could also be considered.
Limited data about this interaction for high-dose inhaled budesonide indicate that marked increases in plasma levels (on average four-fold) may occur if itraconazole, 200 mg once daily, is administered concomitantly with inhaled budesonide (single dose of 1000 µg).
Raised plasma concentrations of and enhanced effects of corticosteroids have been observed in women also treated with oestrogens and contraceptive steroids, but no effect has been observed with budesonide and concomitant intake of low dose combination oral contraceptives.
Because adrenal function may be suppressed, an ACTH stimulation test for diagnosing pituitary insufficiency might show false results (low values).
